1. Field of the Invention
This invention is related to a fuel injection valve and in particular to one with a movable valve seat.
2. Description of the Prior Art
In conventional four-stroke internal combustion engines, the electromagnetic fuel injection valve is mounted in the intake manifold and the pressure at the outlet of the injection valve is lower or equal to the atmospheric pressure, so that a low pressure fuel injection system (about 2-3 kg/cm.sup.2) will suffice for efficient working.
However, for two-stroke internal combustion engines, it is proposed to inject fuel or fuel-air mixture after the exhaust port is closed, in order to reduce the amount of fuel leaking into the exhaust pipe at the time of scavenging. Hence, it is necessary to mount the injection fuel valve on the cylinder. Although a high pressure injection system is workable in this case, it will increase the cost. If a low pressure injection system is used, it is necessary to use a mushroom valve in order to prevent the gas from flowing reversely into the fuel system, as described in U.S. Pat. No. 4,986,247, Kushibe et al 1/1991, and U.S. Pat. No. Re. 34,945 Sayer et al 5/1995. Although the air auxiliary fuel injection valve can promote the atomization of fuel, it is still impossible to obtain the optimum fuel distribution.
Therefore, it is an object of the present invention to provide an improved fuel injection valve which can obviate and mitigate the above-mentioned drawbacks.